Stability of Aspirin in Liquid and Semisolid Bases II: Effect of Fatty Additives on Stability in a Polyethylene Glycol Base

Abstract

Aspirin decomposes rapidly when incorporated into mixtures of polyethylene glycols, but aspirin incorporated into fatty-type suppository bases is much more stable. Fats of vegetable origin were incorporated into a polyethylene glycol base in an attempt to inhibit the decomposition of aspirin in this type of mixture. The process is temperature dependent and refrigeration of the mixture greatly slows decomposition. Degradation was retarded at 26°, but little effect was noted at 4 and 45° within the time limits of this study.